It is recommended that children should brush their teeth for at least 45-60 seconds, and adults for at least 90 to 120 seconds. Most people, especially children, do not brush their teeth for a sufficient period of time to obtain maximum benefit, and moreover have difficulty accurately estimating the time necessary to brush the teeth.
Toothpastes comprising films, which deliver a color change signal after brushing for appropriate period of time, and optionally deliver an active ingredient during the brushing period have been described in the art, most notably in PCT/US2011/065308 (Colgate-Palmolive Company). These toothpastes encourage users to brush their teeth for a longer period of time.
However, a problem associated with the use of such toothpastes is the staining of surfaces when the toothpaste is disposed of (e.g. toothpastes which has been expectorated (spit out) into a sink). The staining is caused by the dissolution of any undissolved film left in the toothpaste as it is being disposed.
Therefore, there is still a need in the art for toothpastes comprising films which deliver a color change signal after brushing, but minimizes or eliminates the staining of surfaces when the toothpaste is disposed of.